This invention relates to a remote control transmitter for transmitting a single RF (radio frequency) signal that contains plural information components.
Many modern vehicles include a RF receiver and small, hand-held transmitters allowing an operator to remotely control different electrical vehicle accessories. Typically, the RF receiver is electrically connected to several vehicle accessories, such as power door locks, power trunk release, interior lights, and/or the horn. The RF receiver includes an antenna which receives or captures local airborne RF signals. Upon receipt of a matching RF signal from an appropriate transmitter, the RF receiver electrically actuates the appropriate vehicle accessory.
The transmitters are sometimes referred to as key fobs. To remotely control different vehicle accessories, the transmitters are pre-programmed to transmit or broadcast several unique RF signals. To actuate a specific vehicle accessory, the transmitters include a set of input switches. The manual depression of each input switch transmits a unique RF signal which actuates a specific vehicle accessory via the RF receiver.
Each transmitter is typically attached to a key ring intended to be placed in a pants pocket or stored in a purse. As a result, the size of the transmitter housing is limited. Accordingly, prior art transmitters have included only a few input switches, usually three or four. The few input switches have restricted the number of vehicle accessories which may be remotely controlled with the transmitters. To increase the functionality of a transmitter, it would be desirable to provide a transmitter capable of remotely controlling at least two vehicle accessories with one input switch.